The purpose of this study is to determine the efficacy, safety, pharmacokinetics and pharmacodynamics of multiple daily IV infusions of RSR13 at a therapeutically relevant daily dose (100 mg/kg) administered immediately prior to radiation therapy in patients with glioblastoma multiforme. This tumor is almost never cured with surgery, radiation therapy or chemotherapy. This research study is designed to look for evidence that RSR13 may improve results of radiation therapy for treatment of this type of tumor and to evaluate the safety and tolerance of RSR13 when given with radiation therapy. RSR13 is an investigational drug that increases the amount of oxygen released from the blood into the tissues. Lack of oxygen in a tumor can reduce the effectiveness of radiation therapy, therefore, RSR13 may improve the effectiveness of radiation therapy by increasing oxygen delivery to the tumor.